Bridge CC 2018 contact sheet with 1000+ photos comes out blank

I'm not sure if I've found a bug or if I'm doing something wrong.

I'm trying to create a large contact sheet set from about 1,400 photos. All the photos are in one folder.

I tried making a small contact sheet with about 100 photos and it worked fine. However, when I select all 1,400 photos and generate a contact sheet, all of the pages come out blank.

The PDF is roughly appropriately sized (the file with 100 photos was about 1.1MB, the one with all 1400 is around 9.5MB), but any PDF renderer shows blank pages.

I tried adding a header/footer and when I do that, those items do appear on the output pages, but the photos are still absent.

I may be able to get this immediate project done by making multiple contact pages (except that the page numbers will be wrong - suppose I can use Acrobat to fix that) but I was wondering if this is a software limit or if this is a bug.

The only other post I've found referencing blank contact sheets had to do with someone who upgraded from Bridge 2017 to 2018 and had to remove some remnants of the Output Module. However, this system is a totally fresh install and has never had Bridge 2017 installed at all.